Quick connect tube couplings

ABSTRACT

Quick-connect couplings having a sleeve with a tubular tube support mounted therein, an internal O-ring, an external O-ring and a collet are configured to retain a tube on the tubular tube support by engaging the tube with the collet. In one embodiment of the invention, the tubular tube support is retained in the sleeve by engagement with a first internal annual shoulder in the sleeve. The interior O-ring positioned against a second annular shoulder within the sleeve. The collet resiliently fits within the sleeve to retain the tubular tube support and internal O-ring in place prior to assembly. An external groove in the sleeve receives an external O-ring to seal with the bore. In another embodiment of the invention, the tubular tube support is staked to a first end of the sleeve by a radially extending flange. The internal O-ring is disposed between the end of the collet and the radially extending flange. An annular trough is provided between the tube support portion and the radially extending flange thereof for receiving the tube. Upon pressing the collet into the sleeve with the tube in place, the tube is locked to provide the quick-connect coupling. An external groove in the sleeve receives an external O-ring for sealing with the bore which receiving the quick-connect coupling. In accordance with a further embodiment, the sleeve has external threads for threading with a standard threaded port,

RELATED PATENT APPLICATIONS

U.S. patent application Ser. No. 08/308,895, filed Sep. 20, 1994pending; U.S. patent application Ser. No. 08/308,906, filed Sep. 20,1994 pending, and U.S. patent application Ser. No. 08/151,880 filed Nov.15, 1993 now U.S. Pat. No. 5,429,394.

FIELD OF THE INVENTION

The present invention relates to quick connect tube couplings, and moreparticularly to improvements in configurations for such couplings.

BACKGROUND ART

Quick-connect tube couplings are used to connect flexible tubes in manydifferent power systems such as, for example, pressured air systems forvehicle air brakes and air conditioning systems which may involveconnections to diverse items such as valve bodies, air tanks and thelike. Each of the tubes require a coupling to connect the end of thetube to a body which may be a conventional fitting, valve, manifold orsimilar device for transmitting and receiving pressurized air.Connecting a tube to a body, or removing a tube from a body, can be atime consuming and expensive task which is frequently performed in thefield where specialized tubes may not be readily available.

There are a wide variety of "push-to-connect" type couplings whichpermit a tube to be quickly and easily connected to a body without theuse of tools. With these couplings, a tube is connected by simply pressfitting the coupling into a bore within the body and then inserting theleading end of the tube into the coupling. Typically, the couplingcontains a plurality of components which releasably retain the tubetherein.

In order for presently used couplings to perform effectively, the boresin the bodies to which the tubes are connected are stepped and formedwith relatively tight tolerances. In order to reduce manufacturingexpenses and lessen the occurrence of coupling malfunctions, it ispreferable to have unstepped bores which can be made with highertolerances. Since currently available couplings require stepped bores,there is a need for new quick-connect tube couplings which functioneffectively with unstepped bore configurations.

As the art progresses to straight bore fittings, fittings are being usedsuch as those set forth in the copending patent applications assigned tothe assignee of the present invention and listed under "Related PatentApplications." It has been found, however, that these fittings requirethe use of larger bores resulting in more material being needed in eachfitting as well as increased space requirements. In addition, previouslydeveloped end fittings require a bore depth which may be critical toproperly seating the coupling and may be excessive for someapplications. In any event, it is desirable to, if possible, reduce theoverall length of quick-connect couplings.

Generally, the prior art over which improvements are being sought isdisclosed in U.S. Pat. No. 5,230,539 issued Jul. 27, 1993, incorporatedherein by reference, which discloses a quick-connect coupling, useful toconnect tubes within a stepped bore in a body. This coupling includes atubular tube support of an outside diameter suitable for frictionallyengaging the inner wall of a tube and a sleeve, the sleeve having aninner diameter greater than the outer diameter of the tube and an outerdiameter complementing the diameter of the bore. The tubular tubesupport has a radial projection extending therefrom. A collet having anouter diameter complementing the inner diameter of the sleeve and aninner diameter greater than the outer diameter of the tubular tubesupport is inserted into the sleeve. The tube is fictionally retained inplace between the collet and the tubular tube support. An O-ring seal isprovided for sealing with the bore.

As the advantages of push-to-connect fittings become increasinglyaccepted, other applications for those fittings are sought. However, asthese fittings are currently configured, ready adaptation is notfeasible.

SUMMARY OF THE INVENTION

In view of the aforementioned considerations, it is a feature of thepresent invention to provide new and improved quick-connect couplingswhich are useful for insertion into unstepped bores, as well as usefulfor other applications, such as air tanks and the like.

The present invention relates to a quick-connect coupling, useful toconnect tubes within a bore in a body or bushing. The coupling includesa tubular tube support of an outside diameter suitable for frictionallyengaging the inner wall of a tube and a sleeve having an inner diametergreater than the outer diameter of the tube and an outer diametercomplementing the diameter of the bore for retaining the sleeve in thebore. The tubular tube support has a radial projection extendingtherefrom. A collet is provided. The collet has an outer diametercomplementing the inner diameter of the sleeve and an inner diametergreater than the outer diameter of the tubular tube support, which innerdiameter is slightly less than the outer diameter of the tube. The tubeis frictionally retained between the collet and the tubular tubesupport. An O-ring seal is disposed around the coupling for sealing withthe bore. The improvement to the quick connect coupling comprises firstand second ends on the sleeve with a first step within the sleeveproximate the first end and a second step between the first step and thesecond ends of the sleeve. The first step engages the radial projectionof the tube support and the second step supports an inner O-ringdisposed within the sleeve for the sealing with the tube when the tubeis inserted therein. With this improvement, the collet retains all ofthe parts within the sleeve during shipping and handling.

In another aspect, the present invention is directed to a quick-connectcoupling, useful to connect tubes within bores formed in bodies. Thecoupling includes a tubular tube support of an outside diameter suitablefor frictionally engaging the inner wall of a tube and a sleeve havingan inner diameter greater than the outer diameter of the tube and anouter diameter complementing the diameter of the bore. A collet havingan outer diameter complementing the inner diameter of the sleeve and aninner diameter greater than the outer diameter of the tubular tubesupport in provided. The inner diameter of the collet is slightly lessthan the outer diameter of the tube, wherein the tube is frictionallyretained between the collet and the tubular tube support. At least oneO-ring seal for sealing with the bore. The improvement comprises aconnection at one end of the sleeve for fixing the tubular tube supportthereto. The tubular tube support has a tube support portion and amounting flange which is joined to the tube support portion by anL-shaped portion having an axially extending section connected to themounting flange and a radially extending section connected to the tubesupport portion to form an annular trough between the axially extendingsection and tube support portion. The annular trough receives the end ofthe tube. An interior O-ring is disposed between the radially extendingmounting flange and the end of the collet for sealing with the tube.

In accordance with more specific aspects of the invention, thequick-connect coupling may be used for connections to tanks, such as airtanks, and may have a threaded portion on the sleeve for threading intothe threaded bores.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other features and attendant advantages of the present inventionwill be more fully appreciated as the same becomes better understoodwhen considered in conjunction with the accompanying drawings, in whichlike reference characters designate the same or similar parts throughoutthe several views, and wherein:

FIG. 1 is a cross-sectional view illustrating a push-to-connect couplingconfigured in accordance with a first embodiment of the presentinvention;

FIG. 2 is a cross-sectional view illustrating a push-to-connect couplingconfigured in accordance with a second embodiment of the presentinvention;

FIG. 3 is an end view of the push-to-connect coupling of FIG. 2;

FIG. 4 is a side view, partially in cross-section, illustrating use ofthe push-to-connect coupling of the present invention in an unsteppedbore of a valve body;

FIG. 5 is a side view, partially in cross-section illustrating anembodiment of the present invention in which a sleeve of the coupling isprovided with external screw threads;

FIG. 6 is a side view, partially in cross section illustrating thepush-to-connect coupling of the present invention configured forassembly with a retainer cup useful for making a connection with an airtank; and

FIG. 7 is a side view, partially in cross section, illustratingutilization of the push-to-connect coupling with air tank.

DETAILED DESCRIPTION

The present invention is an improvement in the type of quick-connecttube coupling disclosed in U.S. Pat. No. 5,230,539 issued Jul. 27, 1993and incorporated herein by reference.

Referring now to FIG. 1, there is shown a first embodiment of aquick-connect tube coupling 10, configured in accordance with theprinciples of the present invention, wherein the quick-connect tubecoupling is comprised of a sleeve 12, a tube support 14, an internalO-ring 16, an external O-ring 18 and a collet 20. A flexible tube 22 isreceived over a first portion 24 of the tube support 14 and isfrictionally retained thereon when collet 20 is slid over the tube.

The sleeve 12 is made of a single piece of brass and includes a firstinternal step 26 and a second internal step 28. The first internal step26 supports a radial fold 30 of the tube support 14 proximate a firstend 31 of the sleeve 12. The radial fold 30 forms a radial projectionwhich extends radially of the tube support 22 and joins a second section32 of the tube support to the first section 24. The second internal step28 supports the internal O-ring 16 which seals with the tube 22 when thetube 22 is shoved into the sleeve 12 over the first portion 24 of thetube support 14. The sleeve 12 has an external annular groove 34proximate the second end 35 of the sleeve which receives the externalO-ring 18 that seals with the bore of a body which receives thequick-connect coupling 10 (see FIG. 4).

Quick-connect coupling 10 is assembled by first installing the tubesupport 14 in the sleeve 12 through the second end 35 of the sleeve andthen inserting the O-ring 16 in the sleeve so as to rest on the secondinternal shoulder 28. The collet 20 is then inserted and the externalO-ring 18 placed in the groove 34 of the sleeve. An advantage of theembodiment 10 of FIG. 1 is that it utilizes a standard tube support 14and can be fabricated utilizing existing manufacturing machinery.Moreover, the components remain together after assembly so that no plugis needed to keep the parts assembled during handling and shipping.

Referring now to FIGS. 2 and 3, there is shown a second embodiment 50 ofa quick-connect coupling configured in accordance with the principles ofthe present invention. The quick-connect coupling 50 includes a sleeve54, unitary tubular tube support 56 an internal O-ring 58, an externalO-ring 60 and a collet 62. As with the embodiment of FIG. 1, thequick-connect coupling 50 is used to connect a tube 63 to some otherelement such as a single step bore, air tank or other bore.

The sleeve 54 has a relieved annular end portion 64 at a first end 65thereof which defines an annular shoulder 66. The annular shoulder 66supports a radially extending flange 68 extending from the tube support56. The radial flange 68 is connected to the tubular tube support 56 bya radial flange portion 70 comprised of an axially extending section 72and a radially extending L-shaped section 74. Between the axiallyextending section 72 and a tube engaging section 76 of the tube support56 is an annular trough 78 which receives the end of the tube 63.

As is seen in FIG. 3, the radially extending flange 68 is staked by aplurality of stakes 80 to the annular shoulder 66 at the first end 65 ofthe sleeve 54. Preferably, the stakes are four in number. Alternatively,the flange 66 is retained with a roll/coin edge that engages the end ofthe sleeve 54. The internal O-ring 58 rests on the radial flange 68 ofthe tubular tube support 56 while the external O-ring 60 is received andan annular external groove 82 in the sleeve 54 proximate the second end83 of the sleeve. As with the embodiment of FIG. 1, the collet 62 slidesinto the sleeve 52 to secure the tube 63 against the sleeve engagingportion 76 of the tubular support 56.

The assembly sequence of the embodiment of FIGS. 2 and 3 is as follows:the collet 60 is inserted into the sleeve 54 followed by insertion ofthe internal O-ring 66 from the second end 83 of the sleeve. The tubesupport 56 is then installed and staked to the sleeve 54. Finally, theexternal O-ring 60 is inserted into the external groove 82 on the sleeve54. As with the first embodiment 10 of the quick-connect tube coupling,the second embodiment 50 remains integral after assembly and does notrequire a plug to keep the component parts assembled. This isadvantageous since the expense of the plug may be avoided.

There are a number of advantages to the second embodiment of FIGS. 2 and3 such as lower "body costs" due to less material and the ability to usea faster machine for manufacturing. The assembly steps are quicker, yetthe quick-connect coupling 50 has the same performance as thequick-connect coupling 10, but has a smaller size in that it is shorter.For example, the quick-connect coupling 50 of FIGS. 2 and 3 has a lengthof 0.910 inch whereas the quick-connect coupling 10 of FIG. 1 has alength of 1.100 inch. Since millions of these quick-connect couplingsare utilized, this decrease in length results in substantial monetarysavings.

Referring now to FIG. 4, there is shown a first arrangement forutilizing the quick-connect coupling 50 of FIGS. 2 and 3 wherein thequick-connect coupling 50 is utilized with a body such as a valve body90 having an unstepped bore 92 aligned with a passage 94. Thequick-connect coupling 50 is configured as a press-in capsule using asleeve 52 which may be made of plastic, brass of aluminum. The sleevehas first and second annular barbs 96 and 98 having edges 100 and 102disposed on opposite sides of the external O-ring 60 which barbs biteinto the cylindrical wall of the straight bore 92 to prevent withdrawalof the quick-connect coupling 50. At the front end thereof, thequick-connect coupling has a rim 104 having a diameter substantiallygreater than the diameter of the straight bore 92 which acts as a stopupon engaging the outer surface 106 of the body 90 to axially positionthe quick-connect coupling 50 in the bore 92. The depth of the bore 92is therefore not critical and need be only long enough to accommodatethe length of the coupling 50.

Referring now to FIG. 5, there is shown a second configuration 50' forthe quick-connect coupling 50 wherein the sleeve 54' has essentially thesame internal construction as the sleeve 54 but wherein the sleeve 54'has a different external configuration. Instead of having externalbarbs, the sleeve 50' has an external thread 110. The thread 110 isdisposed at the inboard end of the sleeve 54' with the external O-ring60 disposed between a nut 112 and the threads 110. The threads 110 arestandard SAE threads which screw into a standard SAE port (not shown).In this way, ports which are configured for screw-in fluid couplings cannow utilize quick-connect couplings.

Referring now to FIG. 6, where a third configuration 120 of the secondembodiment of the quick-connect couplings shown in FIGS. 2 and 3 isillustrated, it is seen that the sleeve 122 now has an annular shoulder124 projecting radially therefrom. The annular shoulder 124 cooperateswith a retaining cup 126 which is stamped from steel or brass andincludes a plurality of lances 128 that are engaged in a groove 130formed in the periphery of a weld bushing 132. The weld bushing 132 hasan unstepped bore 133 and is secured by a weld 134 in a position alignedwith an opening 136 through the wall 138 of an air tank (not completelyshown). With this arrangement, a weld bushing, 132, is provided whichhas no internal steps and allows easier tank weld testing. The fitting120 is installed by sliding the fitting axially with respect to the weldbushing 132 until the lances 128 in the retainer cup 126 snap into thegrooves 132. By simply removing the retainer cup 126, it is easy toreplace a damaged, worn or leaking quick-connect coupling 120 with a newcoupling. Moreover, the quick-connect coupling need not extend into theinterior of the air tank defined by the wall 138.

Referring now to FIG. 7, there is shown an arrangement wherein a fourthconfiguration 150 of the quick-connect coupling of FIGS. 2 and 3 isshown wherein the quick-connect coupling is configured for use with anair tank (not completely shown) defined by wall 152. In the arrangementof FIG. 7, a weld bushing 154 having a stepped bore 155 is welded by aweld 156 to the wall 152 of the air tank in alignment with a circularhole 158 through the wall. In order to prevent the quick-connectcoupling 150 from falling into the tank, the weld bushing 154 has aninterior annular shoulder 160 thereon which serves as a stop against anexterior annular shoulder 162 on the sleeve 164 of the quick-connectfitting 150. Shoulder 162 has a major annular face 168 which facesoutwardly and is engaged by a spring retainer clip 170 seated within aninternally facing annular groove 172 in the bore 155 of the weld bushing154.

With respect to quick-connect couplings for tanks, the arrangement ofFIG. 6 is in most cases preferred because the bore 133 of the weldbushing 132 is unstepped. The annular shoulder 124 of the sleeve 22serves as a stop instead of cooperation between the shoulders 160 and162 serving as a stop, which is the case with the quick-connect coupling150 of the embodiment in FIG. 7. Accordingly, the advantages using anunstepped bore while still having a positively engaged assembly areachieved in the embodiment of FIG. 7.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

What is claimed is:
 1. In a quick-connect coupling, useful to connect atube within a bore formed in a body, wherein the coupling includes atubular tube support of an outside diameter suitable for frictionallyengaging the inner wall of a tube; a sleeve having an inner diametergreater than the outer diameter of the tube and an outer diameterengaging the diameter of the bore; a collet having an outer diameterengaging the inner diameter of the sleeve and an inner diameter greaterthan the outer diameter of the tubular tube support and slightly lessthan the outer diameter of the tube, wherein the tube is frictionallyretained between the collet and the tubular tube support, and anexterior seal for sealing with the bore: the improvement comprising:afirst end of the sleeve being fixed to the tubular tube support thetubular tube support having a tube support portion and a mounting flangejoined to the tube support portion by an L-shaped portion having anaxially extending section connected to the mounting flange and aradially extending section connected to the tube support portion to forman annular trough between the axially extending section and tube supportportion for receiving the end of the tube, the radially extendingmounting flange being fixed to the first end of the sleeve; an interiorO-ring disposed between the radially extending mounting flange and theend of the collet for sealing with the tube; and an exterior annulargroove in the sleeve for receiving the exterior seal.
 2. The improvementof claim 1, wherein the radially extending mounting flange of thetubular tube support is staked to the sleeve.
 3. The improvement ofclaim 1, wherein the sleeve has external annular barbs thereon forengaging an internal surface of a bore to prevent withdrawal of thequick-connect coupling from the bore.
 4. The improvement of claim 3,wherein the sleeve has a rim proximate the second end thereof having adiameter greater than the diameter of the bore for engaging the body inwhich the bore is formed to provide a stop for the coupling, whereby thebarbs prevent the coupling from being withdrawn while the stop limitsthe insertion depths of the coupling.
 5. The improvement of claim 3,wherein the external groove is disposed between a pair of the annularbarbs.
 6. The improvement of claim 1, wherein the sleeve has an externalthread for threading with a complementary threaded port.
 7. Theimprovement of claim 6, wherein the sleeve has a nut unitary therewithat the second end spaced from the external thread and wherein theexterior seal is disposed in the space between the nut and the thread.8. The improvement of claim 1, wherein the sleeve has a radiallyextending shoulder positioned adjacent the first end with the externalgroove for receiving an external O-ring forming the exterior sealdisposed between the radially extending shoulder the second end of thesleeve; the improvement further including a retainer cup which overliesthe shoulder on a face thereof facing the second end of the sleeve, theretainer cup further having an axially extending collar portion with atleast one fastener thereon for fastening with a weld bushing.
 9. Theimprovement of claim 8, wherein the collar portion of the retainer cuphas lances which latch with the weld bushing and wherein the weldbushing has an unstepped bore for receiving the sleeve of thequick-connect coupling.
 10. The improvement of claim 8, wherein the weldbushing has an unstepped bore and is welded to the exterior wall of anair tank proximate an opening therethrough with which the tube retainedby the quick-connect coupling communicates.
 11. The improvement of claim1, wherein the sleeve has a shoulder thereon having a face, facingtoward the second end of the sleeve and a step facing toward the firstend of the sleeve with the external groove for receiving an externalO-ring forming the external seal positioned between the step and thefirst end of the sleeve, and wherein the quick-connect coupling isadapted to coupled with a weld bushing welded to a tank having aninternal step engaged by the external step of the sleeve and a lock forengaging the face of the shoulder on the sleeve for axially retainingthe sleeve within the bore of the weld bushing.
 12. The improvement ofclaim 11, wherein the lock is comprised of an inner annular groove and aretainer clip disposed within the inner annular grove, which retainerclip engages the front face of the shoulder.
 13. The improvement ofclaim 1, wherein the external seal is an O-ring.